8+ Best Transactional SMTP Service Plugins (Compared) 2025

Are you looking for the best transactional SMTP service plugins?

SMTP (Simple Mail Transfer Protocol) makes sure your transactional emails are delivered to users’ inboxes (and not the spam folder). It even lets you automate emails depending on the actions and behavior of your users.

The hard part is finding the right SMTP service since many email services are on the market. but it can be even harder to find the right SMTP service with the right plugin to help you.

Let us help you with this problem with our article on the best WordPress SMTP plugins.

What are SMTP Services

Emails are one of the best ways to communicate with your users. You can nurture them from leads to customers using a series of emails.

But, the problem is that the default WordPress mailer uses the wp_mail() function, which relies on the PHP mail() function. This can lead to unreliable email delivery.

This is just a fancy way of saying that the default way WordPress sends emails depends on your web hosting server to handle the process.

Unfortunately, this setup isn’t very reliable because many servers aren’t properly configured for sending emails. As a result, your emails might get lost, end up in spam folders, or not send at all.

That is why we recommend you use an SMTP service, Simple Mail Transfer Protocol.

SMTP services ensure your emails reach the intended recipient without being lost in transit. It handles the complexities of routing emails across different servers, ensuring they reach their destination efficiently.

Plus, they provide error codes and messages if an email cannot be delivered. For example, a full inbox or an incorrect email address will trigger a bounce message, helping the sender understand the issue.

Tip: if you want to increase your open rate after setting up an SMTP service, use this Free Email Header Analyzer.

Importance of SMTP Plugins for WordPress

At IsItWP, we ran tests to see if using an SMTP service to send transactional emails is convenient. We tested SparkPost, Mailjet, SendPulse, and many more. They helped us improve delivery and email authentication. These factors made them quite reliable.

But, we manually had to set them up on our WordPress site, which was complex and time-consuming. We had to add the SMTP server details, such as host, port, username, and password, directly to your WordPress wp-config.php file.

For others, like Amazon SES, we had to connect it with an API, which, while simpler, was not ideal for beginners.

After this, we understood that using an SMTP plugin was a better solution to send transactional emails.

An SMTP plugin allowed us to set up a reliable WordPress mailing process without coding or technical knowledge.

They integrate seamlessly with popular plugins like WooCommerce, ensuring transactional emails like order confirmations, payment receipts, shipping notifications, and password resets are sent reliably.

SMTP plugins include additional tools like email logs, notifications for failed emails, and testing tools to verify settings. The best part is that the top SMTP plugins allow you to switch between SMTP services without significant changes to your site.

Follow our tutorial here: How to Set Up and Configure SMTP in WordPress. We also have a guide specifically for WooCommerce stores on How to Fix WooCommerce Email Issues.

Because of these findings, we have thoroughly tested many SMTP plugins to see which ones work best in sending transactional emails.

We focused on:

• Ease of setup
• Flexibility and SMTP service compatibility
• security
• reports and analytics
• customization
• pricing

This research and hands-on experience have allowed us to understand the best SMTP plugins fully. In this article, we will break down their features, pros and cons, customization, and more.

Best SMTP Plugins for Transactional Emails Compared

Now, if you do not have time to go through the entire list of the best transactional SMTP services plugins, check out the table for a quick overview.

You can click on the names of the SMTP plugins to skip to that section of the article.

1. WP Mail SMTP

WP Mail SMTP is one of the best plugins for sending transactional emails on WordPress. This is because of its simplicity and high deliverability. As a result, WP Mail SMTP ensures your emails reach the inbox without getting lost in spam folders.

Setting it up is quick and easy, even for beginners. The plugin integrates seamlessly with popular email services like Gmail, SendGrid, Mailgun, and many others.

You don’t need to deal with complicated configurations, making it an excellent choice for those new to WordPress. One of the standout features of WP Mail SMTP is its ability to handle various transactional emails.

It can help you set up emails for registration confirmation, password reset, order update, or even shipping notifications. Another powerful feature is the built-in email logging. You can easily track email delivery, making sure all your transactional emails are delivered successfully.

This gives you peace of mind that your communications are reaching your customers. This SMTP plugin also comes with detailed analytics, allowing you to filter and assess email performance, which can help optimize future communications.

What’s more, WP Mail SMTP supports email authentication protocols like SPF, DKIM, and DMARC.

This helps improve the trustworthiness of your emails, reducing the chances of them being marked as spam by email providers. This is critical for businesses that rely on email as a primary communication tool.

Overall, WP Mail SMTP provides a reliable, user-friendly solution for confidently sending transactional emails. It’s perfect for anyone looking to improve email deliverability and streamline communication.

Check out the latest WP Mail SMTP review here.

Get started with WP Mail SMTP here.

Pricing: Offers a free plugin. The basic plan starts from $49/ Year.

2. SendLayer

SendLayer is the most reliable SMTP transactional email service with a powerful plugin to help you easily set up. It ensures your emails appear in the user’s inbox as quickly as possible.

What we love about it is that you can easily connect and send your website emails using the SendLayer API. No complex processes.

It makes it easy for just about anyone to start sending emails and notifications that include:

• Transactional email
• Registration emails
• Confirmation emails
• Shipping notifications
• Password Resets
• Cart abandonment

Whatever you need with SMTP, SendLayer has you covered. It works seamlessly with 1000+ platforms. Some of the most popular ones include WordPress, WooCommerce, BigCommerce, Joomla, Drupal, and HelpScout.

With SendLayer, you won’t have to worry about what programming language (such as PHP or Python) you use to build your site or app. Your emails will work!

It doesn’t end there. When you sign up for SendLayer, you get access to rich features like mailing lists and groups for easier management. Also, you get a detailed email log to track the full email journey and verify that your emails are making it to their destination.

Added to all this, there are built-in analytics that you can filter by email, status, recipient, and more so you can optimize performance accordingly.

While we’ve covered the basics, SendLayer has much more to offer. Learn more about SendLayer’s transactional SMTP service.

Get started with SendLayer here.

Pricing: Offers a free trial. Premium plans begin at only $5 per month.

3. SMTP

SMTP is the most powerful email delivery service on the market. Its plugin lets you send and track high volumes of emails. And it has a highly responsive infrastructure that ensures speedy deliveries without any delays.

SMTP lets you send all types of transactional emails as well as marketing emails. This includes automated emails like order confirmations, shipping notifications, order status updates, user authentication, and password resets.

With this plugin, your email process will be smooth and seamless to improve user experience on your site. Plus, all plans come with a Reputation defender (add-on). This monitors your email list health and safeguards you against both soft and hard bounces.

The setup and integration process is quick and straightforward so you can start sending emails immediately. Plus, it gives you access to comprehensive reports on your email delivery and engagement performance.

SMTP suits all kinds and sizes of businesses and it lets you can scale your email volume as your business grows. It’s hands down the best SMTP relay and email delivery service worldwide.

Get started with SMTP here.

Pricing: The basic plan costs $25 per month. You can try out the service for free for 30 days with a limit of 50,000 emails.

4. Brevo

Brevo (formerly SendinBlue) is a popular email marketing platform. After you set up its plugin, you can send transactional emails to your subscribers’ lists and track the emails to find out the open rate, bounce rate, click rate, etc. Brevo also offers SMS marketing services to send promotional and transactional messages.

One thing that stands out about Brevo is that they manage SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) signatures through their domain names. This is a technical standard that helps protect email senders and recipients from spam, spoofing, and phishing.

Other notable features of the Brevo plugin include drag and drop email builder, welcome emails, confirmation emails, A/B testing for emails, and advanced reporting for an optimized email marketing campaign.

Check out the latest Brevo review here.

Get started with Brevo here.

Pricing: 300 emails/day with unlimited contacts are free. Starting cost for the basic plan starts from $8.08/ Month.

5. Mailgun

Mailgun is a powerful email service plugin for professional developers. It offers high email deliverability, and with its powerful APIs, you can send, receive and track transactional emails easily.

Mailgun even has advanced email validation to increase your conversions.

It features a robust sending infrastructure with SMTP integration and a simple RESTful API to send bulk emails to your users.

When you sign up for Mailgun, you get access to responsive transactional email templates that are ready to edit and use. You can use the drag and drop editor to quickly create stunning emails without using HTML and CSS. Mailgun also comes with easy-to-use email marketing tools like segmentation, personalization, and A/B testing. 

Get started with Mailgun here.

Pricing: It’s free for 30 days with a limit of 100 messages a day. After the trial, by default, you’ll be moved to the Basic 10K plan, which costs $15/ Month. You can also choose your own plan or opt for a pay-as-you-go service.

6. SendGrid

SendGrid is a cloud-based SMTP transactional email pplugin that comes with a reliable platform to send and receive bulk emails with high delivery rates.

Aside from sending transactional emails, they also allow you to create email marketing campaigns. You can create an exceptional email program using the email API option to deliver emails at scale.

It comes with a variety of integration options for you to start sending emails. You can get a complete analytics and metrics report and real-time feedback on every email you sent.

If you’re looking to use a dedicated IP address for email sending, SendGrid offers this under their Pro Email API plan or an Advanced Marketing Campaigns plan.

Get started with SendGrid here.

Pricing: In the first month, you can send 40,000 emails for free. After that, it offers 100 emails/day forever free plan. The essential plan starts at $19.95 per month for up to 50,000 emails. The price increases with the number of emails you need to send.

7. Postmark

Postmark by ActiveCampaign is one of the best SMTP transactional email plugins that offer lightning-fast delivery for your application and transactional emails. It has SMTP servers distributed around the world to ensure fast email delivery.

It has an excellent tracking system that allows you to monitor how many emails are opened and how much time is spent on the email you send.

Get started with Postmark here.

Pricing: The basic plan costs $15 per month for 10,000 emails. You’ll need to pay $1.80 per 1,000 emails for additional emails.

8. Moosend

Moosend is an affordable SMTP transactional email service plugin that comes with a drag and drop email builder to design your transactional emails instantly. It has a whopping deliverability rate of 98%, which means it can combat spam filters.

This SMTP plugin allows you to create an email blast and tracks the emails in real time. You can also get advanced analytics reports for your transactional emails.

One thing to remember is that Moosend only has a form to get in touch with the support team. There’s no phone, email, or chat support.

Get started with Moosend here.

Pricing: It’s free for 30 days. After that, it starts at $9 per month for 500 subscribers. You’ll get it at $7 per month if you choose to bill annually. All plans offer unlimited emails and campaigns each month.

The Best SMTP Services Without a Plugin

The main focus of this article was to list the best SMTP services that come with a plugin for ease of use. But, we also want to mention some of the best SMTP services that do not have a WordPress plugin.

The reason we have included them in this list is because, despite their lack of a plugin, they are still easy to use and set up. All you need is the APIs.

9. Amazon SES

Amazon SES is a flexible and scalable SMTP transactional email service, which is primarily geared towards application developers and digital marketers. It helps you easily send notifications and transactional emails to your users. It allows you to use the SMTP interface or an Amazon SES API to integrate Amazon SES directly into your application.

Amazon SES comes with a robust system and functionality that makes sure your emails ignore the spam filters. You can track email delivery, bounce rate, and rejections through their smart mechanism.

Get started with Amazon SES here.

Pricing: It’s a pay-as-you-go service, which means you’ll need to pay for what you use. It allows you to send 62,000 emails per month for free. After the free limit, you’ll need to pay $0.10 for every 1,000 emails. If your emails include attachments, then you’ll have to pay $0.12 per GB.

10. Mailchimp Transactional Email

Transactional Email, formerly called Mandrill, is an SMTP transactional email service by MailChimp. It’s a secure and efficient platform to send transactional emails without any delivery issues. You can use Transactional Email to send data-driven, targeted, personalized, and eCommerce emails to your users.

With its advanced tracking, you can monitor the open rate, bounce rate, and click rate for your emails. Added to that, the Mailchimp platform gives you access to email templates and email campaigns for better marketing strategies.

Get started with Transactional Email here.

Pricing: There’s a forever free plan with 2,500 emails and 500 contacts. It costs $6.50 for 5,000 emails/month. The cost increases with the number of emails and subscribers you have.

That’s our list of the best SMTP services. If you’re looking for more options, there’s MailJet and SparkPost. Keep in mind that Gmail is not a good option for transactional emails. They have many restrictions and you’ll likely face a ton of hiccups with your emails.

It’s best to use a dedicated SMTP service. Now since this is a long list, you may still be wondering which is the best one. We give you our verdict below.

What are the best transactional email services?

When choosing the best SMTP service, you’ll want to look at important factors:

• Sender reputation
• Scalable infrastructure
• Marketing automation
• Free email plans and affordable paid plans
• Detailed reporting and email analytics

Every SMTP service plugin in this list has something unique to offer, but the one that comes out on top are WP Mail SMTP, SendLayer and SMTP.com. They check all the right boxes and have everything you need in an SMTP service including a robust setup, high delivery rates, and a reliable support team.

For reliable email delivery on a small scale, SendLayer is our #1 pick. If you need more power to send a huge number of emails, SMTP.com is the best for that.

We hope this article helped you find the best SMTP transactional email services. Up next, you may want to see the best CRM software for small businesses.

You’ll also want to check out these related resources:

• Best Email Newsletter Plugins for WordPress
• How to Set Up the Right Form Notification Emails
• How to Grow Your Email List With Social Proof Notifications

These posts will help you create an email marketing strategy that works wonders for your online business.